Aspect Ratio Calculator
.box { aspect-ratio: 43 / 18; }- 16:9 — video/gaming standard
- 16:10 — productivity laptops
- 21:9 (43:18) — ultrawide
- 32:9 — super ultrawide
- 2.39:1 — cinematic scope
- 1:1 / 4:5 / 9:16 — social media
Professional Ratio Calculator
Integer simplification
Any resolution simplified via GCD — 3440×1440 → 43:18, matched to the 21:9 family.
Locked solving
Lock the ratio and solve height from width or vice versa — perfect for design specs.
Overlay visualization
16:9/16:10/21:9/32:9 stacked at equal width make differences obvious.
Ratio Essentials
DAR
Display Aspect Ratio — the pixel ratio this tool computes.
SAR/PAR
Storage/Pixel ratios in video: DAR = SAR × PAR. Square pixels mean PAR=1.
Black bars
Content/screen ratio mismatch produces pillarbox (sides) or letterbox (top/bottom) bars.
How to Use
Enter resolution
Fill width and height; simplified ratio and category update live.
Check the overlay
Compare against common ratios stacked at equal width.
Solve locked
Lock the ratio, type either side, get the other automatically.
Ratio Use Cases
16:9
Universal
- + Most content
- + Game default
- − Less vertical room
16:10
Productivity
- + +11% vertical
- + Office comfort
- − Thin video bars
21:9
Immersive
- + Cinematic
- + Multi-window
- − Patchy support
9:16
Mobile
- + Short-video standard
- − Not for desktop
Practical Tips
Timeline ratio follows platform: YouTube 16:9, TikTok 9:16, Xiaohongshu 3:4.
On 21:9 monitors, true 21:9 sources play with zero black bars.
Use CSS aspect-ratio: 16/9 instead of the padding hack for clean responsive boxes.
If a game lacks ultrawide support, prefer black bars over stretched distortion.
FAQ
Calculation Notes
- Ratios simplified via greatest common divisor
- Category matching uses ±2% tolerance
- Solved values rounded to integer pixels
- Library covers film/social/print ratios
Related Tools
Pair with the Test Wizard for new screens
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